Process for obtaining valuable organic compounds from the acid sludge of mineral oil refining processes



Sept. 12, 1939. K4 BAUER ET AL 2,172,784

PROCESS FOR OBTAINING VALUABLE ORGANIC COMPOUNDS FROM THE ACID SLUDGE OF' MINERAL OIL REFINING PROCESSES Filed March 4, 1937 2 Sheets-Sheet 1 Sept. 12, 1939. K4 BAUER ET'AL 2,172,784

PROCESS FOR OBTAINING VALUABLE ORGANIC COMPOUNDS FROM THE ACID SLUDGE OF MINERAL OIL REFINING PROCESSES `Filed March 4, 1937 2 Sheets-Sheerl 2 lvwewtovs:

El/ E ss/s Patented Sept. l2, 1939 UNITED STATES PATENT OFFICE GANIC COMPOUNDS FROM THE SLUDGE F BUNEBAL OIL REFINING PROCESSES Karl Bauer, Waclaw Junosra v. Piotrowski, Hugo Burstin, and Jzci' Winkler, Drohobycz, Po-

land v .Application March 4, 1937, Serial No. 129,096 In Poland March 23, 1936 11 Claims.

The present invention relates to a method of obtaining fusible organic compounds from acid wastes of mineral oil rening processes.

Acid wastes (named also acid sludge) obtained as a by-product in the refining of mineral oil with sulfuric acid contain mainly the following constituents:

1, Sulfonic acids; 2, free sulfuric acid; 3, neutral organic compounds i. e. occluded minerai oil and asphalt-like products formed by partial oxidation, polymerisation and condensation of mineral oil hydrocarbons; 4, solid carbonaceous substances insoluble in the known solvents.

Many processes have beenrproposed for the manufacturing of valuable products by reiining acid sludges. These processes may be divided into two groups. l

The iirst group comprises methods for obtaining valuable compounds from acid sludge without previous neutralisation of the free sulfuric acid contained therein. To this group belong the processes for regeneration of sulfuric acid with simultaneous production of the bitumen contained in the acid sludge. According to one method the sludge is, for instance, boiled with water, dilute sulfuric acid and free bitumen being thus obtained. Another known way for utilizing rening wastes is the treatment of acid sludge with organic solvents, the organic components such as bitumen, sulfonic acids and others being thereby dissolved and free sulfuric acid separated.

The above mentioned processes are not commercially practical since they require expensive operations while the resulting products, sulfuric acid and bitumen, are of inferior quality and cannot be sold at a reasonable price.

The second group comprises methods of treating acid sludge, in most cases previously neutralized with alkalies or earth alkalies. The neutral- 4.0 ized sludge may be treatedfor instance-with extracting means, in which case the bitumen will pass into the extract. Moreover neutralized sludges may also be used for production of sulfonic acids.

45 These processes are also 'not very profitable becausefor instance-by extraction of the neutralized sludge only part of the organic compounds contained therein are recovered. Furthermore the products obtained by processes 50 of the second group are not of good quality.

Further proposals have been made for obtaining valuable products by distilling the neutralized lsludge in vacuo or in the presence of steam. It has proved, however,`very diihcult or almost 55. impossible to distill a solid mass without decomposition. A dry distillation of such a masswhich is only slightly conductive to heat-always involves at least a partial decomposition of "the higher boiling hydrocarbons.

It is the primary object of the present inven- 5 tion to obtain in an inexpensive and simple manner the organic compounds contained in the acid sludges without decomposition.

We have discovered, and the present process is based on this discovery, that upon moderate heat- 10 ing of the neutralized sludge, there may be caused to separate out on the surface of the dry solid or plastic mass a dark liquid which freely ilows oil', free from inorganic bulk, through the hollow spaces of the mass. The liquid contains 15 the total amount of desired'organic compounds in undecomposed state.

The neutralized sludge must be heated in such a manner that its temperature will not rise above the average boiling temperature of the organic 20 compounds contained in the sludge. In most cases a temperature of 20G-300 C. will be suiilcient to obtain the desired compounds in the liquid state. 'I'he heat necessary for melting out the organic compounds may be imparted to the 25 mass either directly by means of hot vapors or .non-oxidizing gases or mixtures thereof, or the mass may be heated from the outside by indirect supply of heat. In some cases it is advantageous to combine direct and indirect heating. Different 30 forms of apparatus may be used for melting out the organic compounds from the neutralized sludge.

If the neutralized sludge is not of powdery but rather ofv plastic consistency it is advantageous 35 to mix it with a loosening material for instance gravel, slag, coal, coke, limestone' o r the like. By these means hollow spaces are provided through which the liquifled organic compounds freely iiow o. It is also advantageous to admix V40 a well divided material of good heat conductivity such as iron powder, copper shavings and the like.

It is convenient to provide at the lowest point of the apparatus serving for melting out thev fusible organic compounds a layer of granular material consistingfor instance-of one of the above mentioned loosening materials for the purpose of retaining the finest inorganic compoimds carried along.

In some cases, especially if a sludge containing few organic compounds'is treated, it is advantageous to impregnate the dry mass consisting of neutralized sludge with a light mineral oil, for instance, kerosene or gasoil. 'I'hereby the orgarlic compounds will melt out at a lower temperature than if the mass were used in the unwetted state.

The process according to the present invention is described in the following examples and illustrated by the annexed drawings which show two different embodiments of an apparatus for carrying out the process. It should be understood that the invention is, however, not limited by the examples given and by the devices shown in the drawings.

Fig. 1 is a vertical longitudinal/section through the apparatus.

Fig. 2 is a section along line 2-2 of Fig. 1 and Fig. 3 is a vertical longitudinal section through a modied form of the apparatus.

In Figs. 1 and 2 there is shown an oblique retort i mounted within a furnace, the retort being closed at the bottom by an iron basket 3 filled with slag or other lumpy material. The basket 3 is placed in a funnel 2 leading the molten organic liquid through the channel 4 into the receiver 8, which by means of the pipe 9 maybe connected with an exhauster, not shown in the drawings. At the top the retort is closed by a cover with the valve 6 serving for introduction of steam or hot gases, if required. The burner 5 serves as a heating device.

In Fig. 3 the retort diers from the one shown in Figs. 1 and 2 in having a tube 1 arranged therein. This tube is provided with small perforations and serves for better draining off the y molten organic liquid.

Example 1: The retort l is filled to 4/5 of its capacity with a mass consisting of acid sludge neutralized with lime and mixed with 30 per cent. of slag. The cover is put onto the retort which is then heated by the gas-burner 5 to about 275 C. After about l hour a dark liquid consisting of the molten organic compounds begins to flow down the funnel 2. If the apparatus according to Figs. l and 2 is used the liquid is collected in the receiver 8. The total amount of liquified organic compounds is 45 per cent. by weight, calculated on the weight of the acid sludge.

Example 2.' Neutralized sludge is mixed with 20 per cent. of gravel and 5 per cent. of iron turnings. To this mass 10 per cent. by weight of kerosene are added while stirring thoroughly. Thereby the mass is wetted, but should not be allowed to separate a liquid product. Then the mass is poured into the retort I described above. After the retort is closed it is heated by the gas-burner with simultaneous admission of hot combustion gases and a little superheated steam by the valve 6. At about 180 C. the organic compounds begin to melt out. The highest temperature of the mass does not surpass 250 C. From the dark liquid thus obtained kerosene is distilled oil by the use of superheated steam. The output of molten organic compounds, calculated on treated acid sludge, amounts to 42 per cent. by weight.

If desired, the container 8 may be connected by means of pipe 9, with an exhauster sucking off the hot combustion gases and the uncondensed steam, if any, the melting out of the fusible compounds being thereby facilitated. In this case the relative pressure in the retort is reduced about 50 to 100 millimeters mercury.

In the modified apparatus shown in Fig. 3 which may be used for carrying out either of the above examples, the arrangement of tube 1 serves the purpose of providing a free space in the retort which serves as a draining device and facilitates the discharge of the molten organic compounds. Instead of the tube carrying holes some other means can be provided for the same purpose, for instance a mechanical resisting wire gauze separating an empty segment of the ret'ort or the like.

What we claim is:

1. A process for obtaining valuable organic compounds from a chemically neutralized acid sludge derived from mineral oil refining processes and containing fusible organic compounds, which process comprises mlting the fusible organic compounds by heating the sludge at a temperature substantially within the range of 20D-300 C., separating the organic compounds while in the molten condition from the inorganic residue and withdrawing said molten product substantially free from inorganic residue.

2. A process as set forth in claim 1, wherein the melting of lthe sludge is accomplished by treatment with hot gases.

3. A process according to claim 1, wherein the sludge is meltedby indirect heating.

4. A process according to claim 1, wherein the sludge is melted by combined direct and indirect heating.

5. A process for obtaining valuable organic compounds from acid sludge derived from mineral oil refining processes and containing fusible organic compounds, which process comprises heating chemically neutralized acid sludge at a temperature substantially within the range of 200-300 C. in an inclined closed vessel, thereby melting out the fusible organic compounds, separating said organic compounds from the inorganic residue, and draining olf the molten organic materials from the lower portion of the vessel substantially free from inorganic residue.

6. A process according to claim 5, wherein solid inert iiltering material is employed at the lower end of the closed vessel.

7. A process for obtaining valuable organic compounds from the acid sludge of mineral oil refining processes which comprises wetting a chemically neutralized acid sludge containing fusible organic compounds, with a mineral oil of low boiling point, heating the so obtained mass to a temperature below the average boiling temperature of the fusible organic compounds and substantially within the range of 200-300 C., thereby melting said fusible organic compounds, separating the molten organic compounds from the inorganic residue and draining ofi' said molten organic compounds.

8. 'A process for obtaining valuable organic compounds from the acid sludge of mineral oil `reflning processes which comprises adding to a neutralized acid sludge containing fusible organic compounds a solid, inert, loosening material, heating the so obtained mass below the average boiling temperature of the fusible organic compounds and substantially within the range of 200300 C., thereby melting said fusible organic compounds, and'draining of the molten organic compounds substantially free from inorganic residue.

9. A process according to claim 8 in which a loosening material selected from a group consisting of gravel, coal, coke, limestone and slag is used.

10. A process for obtaining valuable organic compounds from the acid sludge of mineral oil refining processes which comprises adding to a neutralized acid sludge containing fusible orgam. compounds a solid heat conductive material, heating the so Untamed mass to a temperature below the average boiling temperature Aof the fusible organic compounds and substantially within the range of 20W-330 C., thereby melting said fusible organic compounds, separating' the molten portion from the inorganic residue and draining of! said molten organic compounds.

11. A process according to claim 10 in which a heat conductive means selected from a. group consisting of iron turnings, iron Raschig rings and copper lings are added.

KARL BAUER.

WACLAW JUNOSZAv. PIOTROWSKI. HUGO BURSTIN.

JzEF WINKLER. 

